package java1224;

public class Java01 {
    public static void main(String[] args) {
        //变量和常量
        //变量：可以变化
        int a =2;
        System.out.println(a);
        a=3;
        a=5;
        a=7;
        System.out.println(a);
        //常量：不能更改、用final关键字修饰
        final int b =6;
        System.out.println(b);
        //数字下划线
        int salary=1_000_000_000;
        double d =3.141592_65358_979;
        System.out.println(d);
        System.out.println(salary);
        //赋值
        int x =3;
        double y=3.0;
        x+=y;
        System.out.println(x);
    }
}
